Modelling of Downhill Timber Skidding: Bigger Load – Bigger Slope
Skidder mobility during timber extraction is defined by: 1) basic dimensional features of the vehicle, 2) ability to overcome obstacles during movement, 3) traction performance and 4) environmental soundness. Traction performance depends on the ground conditions (soil bearing capacity) and the total...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
University of Zagreb, Faculty of Forestry
2016-01-01
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| Series: | Croatian Journal of Forest Engineering |
| Online Access: | https://hrcak.srce.hr/file/226115 |
| _version_ | 1818066922733830144 |
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| author | Andreja Đuka Tomislav Poršinsky Tibor Pentek Dubravko Horvat |
| author_facet | Andreja Đuka Tomislav Poršinsky Tibor Pentek Dubravko Horvat |
| author_sort | Andreja Đuka |
| collection | DOAJ |
| description | Skidder mobility during timber extraction is defined by: 1) basic dimensional features of the vehicle, 2) ability to overcome obstacles during movement, 3) traction performance and 4) environmental soundness. Traction performance depends on the ground conditions (soil bearing capacity) and the total effect of all forces on the vehicle. In downhill skidding, the skidder is under great influence of parallel component of forces, adhesion weight and longitudinal terrain slope, which combined result in negative traction force, torque and thrust force. When the horizontal component of rope force is equal to zero i.e. the moment when the weight of the load and resistance to traction are in equilibrium, the slope angle α is a function of load mass distribution factor and skidding resistance factor. This is a »turning point« that can be defined as a critical slope because the load starts to push the vehicle downhill, which results in negative horizontal component of rope force. Depending on skidder Ecotrac 120V dimensional features, centre of gravity, load mass distribution factor, skidding resistance factor of previous research, five different loads were analyzed (1 to 5 tonnes) in order to define the critical slope angle for each of them. Critical slope for downhill skidding of 1 tonne timber is on longitudinal slope of –26%, for 2 tonne timber on –30%, 3 tonne timber on –34%, 4 timber on –38% and for 5 tonne timber on –43% of terrain longitudinal slope. Even though skidding bigger load increases vehicle mobility to even greater slope angles, the most important in downhill skidding, is to avoid blocking of the wheels, which will lead to a complete vehicle slippage and the driver must be constantly aware of that fact. The general recommendation should be that skidding small loads (1 to 3 tonnes) downhill is suitable for smaller longitudinal terrain slopes (up to maximum –34%), while the heavier the load, the further down the slope the skidder can go. The load of 5 tonnes »anchors« the skidder better and therefore it can go on terrain slopes up to –43%, during which less traction force is used (torque is used for braking) and skidder pulls the load by its own weight. It can be concluded that extending the operating range of skidder onto steeper slopes with heavier loads has the potential to decrease harvesting costs and increase productivity. |
| first_indexed | 2024-12-10T15:15:29Z |
| format | Article |
| id | doaj.art-7c34e6b36bcf4ec686ca329ac66d34a8 |
| institution | Directory Open Access Journal |
| issn | 1845-5719 1848-9672 |
| language | English |
| last_indexed | 2024-12-10T15:15:29Z |
| publishDate | 2016-01-01 |
| publisher | University of Zagreb, Faculty of Forestry |
| record_format | Article |
| series | Croatian Journal of Forest Engineering |
| spelling | doaj.art-7c34e6b36bcf4ec686ca329ac66d34a82022-12-22T01:43:48ZengUniversity of Zagreb, Faculty of ForestryCroatian Journal of Forest Engineering1845-57191848-96722016-01-01371139150153479Modelling of Downhill Timber Skidding: Bigger Load – Bigger SlopeAndreja Đuka0Tomislav Poršinsky1Tibor Pentek2Dubravko Horvat3Department of Forest Engineering, Faculty of Forestry University of Zagreb Svetošimunska 25 10002 Zagreb CROATIADepartment of Forest Engineering, Faculty of Forestry University of Zagreb Svetošimunska 25 10002 Zagreb CROATIADepartment of Forest Engineering, Faculty of Forestry University of Zagreb Svetošimunska 25 10002 Zagreb CROATIADepartment of Forest Engineering, Faculty of Forestry University of Zagreb Svetošimunska 25 10002 Zagreb CROATIASkidder mobility during timber extraction is defined by: 1) basic dimensional features of the vehicle, 2) ability to overcome obstacles during movement, 3) traction performance and 4) environmental soundness. Traction performance depends on the ground conditions (soil bearing capacity) and the total effect of all forces on the vehicle. In downhill skidding, the skidder is under great influence of parallel component of forces, adhesion weight and longitudinal terrain slope, which combined result in negative traction force, torque and thrust force. When the horizontal component of rope force is equal to zero i.e. the moment when the weight of the load and resistance to traction are in equilibrium, the slope angle α is a function of load mass distribution factor and skidding resistance factor. This is a »turning point« that can be defined as a critical slope because the load starts to push the vehicle downhill, which results in negative horizontal component of rope force. Depending on skidder Ecotrac 120V dimensional features, centre of gravity, load mass distribution factor, skidding resistance factor of previous research, five different loads were analyzed (1 to 5 tonnes) in order to define the critical slope angle for each of them. Critical slope for downhill skidding of 1 tonne timber is on longitudinal slope of –26%, for 2 tonne timber on –30%, 3 tonne timber on –34%, 4 timber on –38% and for 5 tonne timber on –43% of terrain longitudinal slope. Even though skidding bigger load increases vehicle mobility to even greater slope angles, the most important in downhill skidding, is to avoid blocking of the wheels, which will lead to a complete vehicle slippage and the driver must be constantly aware of that fact. The general recommendation should be that skidding small loads (1 to 3 tonnes) downhill is suitable for smaller longitudinal terrain slopes (up to maximum –34%), while the heavier the load, the further down the slope the skidder can go. The load of 5 tonnes »anchors« the skidder better and therefore it can go on terrain slopes up to –43%, during which less traction force is used (torque is used for braking) and skidder pulls the load by its own weight. It can be concluded that extending the operating range of skidder onto steeper slopes with heavier loads has the potential to decrease harvesting costs and increase productivity.https://hrcak.srce.hr/file/226115 |
| spellingShingle | Andreja Đuka Tomislav Poršinsky Tibor Pentek Dubravko Horvat Modelling of Downhill Timber Skidding: Bigger Load – Bigger Slope Croatian Journal of Forest Engineering |
| title | Modelling of Downhill Timber Skidding: Bigger Load – Bigger Slope |
| title_full | Modelling of Downhill Timber Skidding: Bigger Load – Bigger Slope |
| title_fullStr | Modelling of Downhill Timber Skidding: Bigger Load – Bigger Slope |
| title_full_unstemmed | Modelling of Downhill Timber Skidding: Bigger Load – Bigger Slope |
| title_short | Modelling of Downhill Timber Skidding: Bigger Load – Bigger Slope |
| title_sort | modelling of downhill timber skidding bigger load bigger slope |
| url | https://hrcak.srce.hr/file/226115 |
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